class Car:
    def __init__(self, model, wheel: int = 4, color: str = None, weight: float = 0, gas: int = 0):
        self.model = model
        self.wheel = wheel
        self.color = color
        self.weight = weight
        self.gas = gas

    def run(self):
        print(f'{self.model} is running ...')


c = Car('法拉利')
d = Car('宝马')
e = Car('宾利')
f = Car('兰博')
c.run()
d.run()
e.run()
f.run()
